I'm a bad girlfriend

Hi! I (F20) and my boyfriend (M20) have been dating for almost 2 years now. Recently he told me he'd been thinking about something for a very long time, because he worries about me and that I'm not taking care of myself enough. My health isn't the best because I'm terrible at working out. I also have pots (basically something that makes me dizzy and tired) so I NEED to workout. I've also struggled a lot with anxiety since I quit antidepressants. I've been overthinking a lot and accidentally taken it out on him. He told me how he felt like he had to worry about me all the time and it was exhausting for him. I completely understand how he feels and respect it. However, he said that if this continues he wants to take a break. I started hyperventilating and crying when he said it. I still understand and respect his feelings, but I feel so incredibly bad partly because I made him feel this way and partly because I'm at risk of losing him. I'm gonna work hard to start working out, eating better and keeping my overthinking to myself. However I'm not really sure how to stop feeling so anxious and scared that he'll leave me. I hope this made sense.